Abstract: The novel amplitude parameters are proposed based on mecroscopic theory for orthotropic sand fabric, the comparative analysis is presented between the magnitude and mecroscopic test results of Toyoura sand. The random arrangement of non-spherical particles naturally forms orthotropic fabric of sand, and the three-dimensional component of its referred orientation are described with two independent angles. Based on the fabric theory of non-spherical particles randomly arranged of sand, the novel amplitude parameters of anisotropic sand on three orthogonal planes are defined. The expressions of the novel amplitude parameters are defined with the mathematical probability statistical methods, the fabric characteristics of discrete particles become the measured parameters in the plane. With the changes of the physical characteristics and geometry of microscopic particles, the amplitude parameters can be used to describe the isotropy, transversely isotropy and orthogonal anisotropy of material. Verification analysis with mecroscopic tests for Toyoura sand shows that the three amplitude parameters can describe the properties in orthogonal plane, the extensive quantitative methods of mecroscopic fabric which own a clear physical meaning are provided.

Key words: sand fabric, orthogonal anisotropy, microstructure, quantitative analysis